This thesis examines how very young children (1-3 years) organize participation during naptime, a recurrent activity of everyday life in preschools. Focus is on how these children practice their social and cultural understandings of the local order and thus establish various local orders as part of how they shape their peer cultures and the routines of the naptime. An ethnomethodological and conversation analytic (EM/CA) perspective is used to explore the organisation of the local orders oriented to by the children in their participation during naptime. A special interest is directed at how small children use embodied actions and various semiotic resources as they actively take part in this preschool routine. The data, collected during fieldwork with participant observations, consist of video recordings and field notes. The recordings are analysed using EM/CA methods, including detailed attention to embodied features of interaction along with spatial and material arrangements. Transcriptions of interaction comprise representations of both verbal and visual aspects, e.g. gestures, gaze and movement through the room. The study shows that naptime involves more than sleep. It is demonstrated how very young children, through interaction with each other and the pedagogues, are active agents in sustaining, creating, re-creating and challenging the local orders of naptime. Through embodied actions and the use of various semiotic resources, the children are able to create time and space for their own peer cultures within this institutional routine. Overall, the study sheds light on the sophisticated ways in which very young children use their knowledge of cultural and institutional routines – the spatial organisation of sleep mattresses, artefacts (e.g. blankets, pacifiers and soft toys) and the sequential structures of the naptime – to constitute spaces for play and joyful interaction with peers and pedagogues. In spite of their sometimes limited vocal language, these very young children are able to use a variety of semiotic resources to constitute their own social life within naptime, often through secondary adjustments to institutional and adult structured order.